We report the analysis of floral fragrance volatiles from two scented amaryllis species, Hippeastrum brasilianum and Hippeastrum parodii. Whereas the headspace of H. brasilianum is dominated by a large peak of (Z)-β-ocimene (88% of total peak area), H. parodii has two large peaks comprising 78%, identified as eucalyptol (1,8-cineole, 30%) and (Z)-β-ocimene (48%). The two species also differ in other constituent compounds. Overall, H. parodii, although producing less total volatile organic compounds (VOCs), has a more diverse bouquet. This species also exhibits an inverse pattern of emission between eucalyptol and β-ocimene, both daily and across the 4-day period from anthesis to senescence of the flower. We compare our results with reports for a complex amaryllis hybrid and a bat-pollinated species, Hippeastrum calyptratum. The hybrid had a very different complement of emissions. The bat-pollinated species shared some of the same constituent volatiles as H. brasilianum and H. parodii, but at lower percentages, and emitted a more diverse assortment of compounds. We conclude that both H. brasilianum and H. parodii attract lepidopteran pollinators but suggest that H. parodii may also attract other insects. We briefly discuss floral fragrance from the perspective of breeding amaryllis.
Evolution of Floral Fragrance Is Compromised by Herbivory
